The Revenge of the Mute Wife by Melanie Paulson

Deborah was abused all her life. During her childhood, she was mistreated by her stepmother and stepsiblings, causing her to lose her ability to speak due to the trauma. As an adult, she thought things would change when she married the man she loved, Roger Peterson, but he hated her with a passion and considered her a nuisance for being mute. Roger was always distant and never cared about the pain he caused her. Instead, his attention fell entirely on his childhood sweetheart, spoiling her and making her his mistress. Afraid of being alone, Deborah endured her marriage to Roger for three years, thinking that if she loved and understood him, he would notice her worth and leave his mistress. But she soon realized that would never happen and had reached her limit. Deborah wanted a divorce to seek her own happiness. Even if Roger refused to out of pride, she wouldn't give up because she had found a reason to fight for her right to live a happy life.